Try "fortuna est imparatis, parati non eam requirunt.", giving: "luck is for the unprepared, the prepared do not need it." Cicero disagrees with yourself: "fortuna, non sapientasapientia, vitam regit" = "Luck, not brains, rules life."
Romans, generally, thought: "contra lucem, vix deus vires habet." Against a lucky man, even a god scarcely has power."